📚 Year 10 CCEA Computer Science: Core Knowledge Review | Year 10 CCEA 计算机：核心知识点梳理
Success in CCEA GCSE Computer Science begins with a solid understanding of Year 10 fundamentals. This article breaks down the core topics you need to master, from binary logic to networking and algorithms. Each concept is explained in both English and Chinese to support bilingual learners.
在 CCEA 的 GCSE 计算机科学中取得成功，首先要扎实掌握 Year 10 的基础知识。本文分解了需要掌握的核心主题，从二进制逻辑到网络和算法。每个概念都以中英双语解释，以支持双语学习者。
1. Computer Systems Basics | 计算机系统基础
The Central Processing Unit (CPU) is the brain of the computer. It fetches, decodes and executes instructions using the control unit (CU), arithmetic logic unit (ALU) and registers like the program counter (PC) and accumulator (ACC).
中央处理器 (CPU) 是计算机的大脑。它通过控制单元 (CU)、算术逻辑单元 (ALU) 以及程序计数器 (PC)、累加器 (ACC) 等寄存器来取指、译码和执行指令。
Main memory consists of RAM and ROM. RAM is volatile and stores currently running programs and data; ROM is non-volatile and holds firmware such as the BIOS. Cache memory sits between the CPU and RAM to speed up access to frequently used data.
主存由 RAM 和 ROM 组成。RAM 是易失性的，存储当前正在运行的程序和数据；ROM 是非易失性的，存放 BIOS 等固件。缓存位于 CPU 与 RAM 之间，可以加快对常用数据的访问。
Secondary storage devices are needed for permanent storage. The table below compares common types:
辅助存储设备用于永久保存数据。下表比较了常见类型：
| Type / 类型 | Speed / 速度 | Durability / 耐用性 | Cost per GB / 每 GB 成本 |
|---|---|---|---|
| Hard Disk Drive (HDD) | Moderate / 中等 | Can be damaged by movement | Low / 低 |
| Solid State Drive (SSD) | Fast / 快 | More durable, no moving parts / 更耐用，无移动部件 | Medium-High / 中高 |
| USB Flash Drive | Moderate / 中等 | Portable but can be lost / 便携但易丢失 | Low / 低 |
2. Data Representation | 数据表示
Computers store all data as binary digits (bits), 0 and 1. A group of 8 bits is a byte. Numbers can be represented in binary, denary (decimal) and hexadecimal (base 16). To convert denary 25 to binary: 2510 = 110012. Hexadecimal uses digits 0-9 and letters A-F; for example, FF16 = 25510.
计算机将所有数据存储为二进制位（0 和 1）。8 个位组成一个字节。数字可以用二进制、十进制和十六进制（基数为 16）表示。将十进制 25 转换为二进制：2510 = 110012。十六进制使用数字 0-9 和字母 A-F；例如 FF16 = 25510。
o 1s are added (1+1=10). Overflow occurs when the result exceeds the bit width, e.g., 11112 + 00012 = 100002 in a 4-bit register causes a carry out.
二进制加法采用与十进制相同的列相加法，当两个 1 相加（1+1=10）时会产生进位。当结果超出位宽时发生溢出，例如在 4 位寄存器中，11112 + 00012 = 100002 会产生进位出。
Characters are stored using character sets. ASCII uses 7 bits, representing 128 characters, while Unicode supports many more to cover global languages. Images are stored as a grid of pixels; each pixel's colour is represented by a binary value. Higher colour depth (bits per pixel) gives more colours. Sound is sampled at a certain rate (e.g., 44.1 kHz) and bit depth. File size can be estimated as:
字符使用字符集存储。ASCII 使用 7 位，表示 128 个字符，而 Unicode 支持更多字符以涵盖全球语言。图像存储为像素网格；每个像素的颜色用二进制值表示。颜色深度（每像素位数）越高，可表示的颜色越多。声音按一定的采样率（如 44.1 kHz）和位深度进行采样。文件大小可估算为：
File size = sample rate × bit depth × duration (seconds) × number of channels
文件大小 = 采样率 × 位深度 × 时长（秒）× 声道数。
3. Logic Gates and Truth Tables | 逻辑门与真值表
Logic gates are the building blocks of digital circuits. The three basic gates are AND, OR and NOT. Each produces an output based on Boolean inputs. Their truth tables are essential for analysis:
逻辑门是数字电路的构建块。三种基本门是与门、或门和非门。每个门根据布尔输入产生输出。它们的真值表对于分析至关重要：
| A | B | A AND B | A OR B |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 |
| 1 | 0 | 0 | 1 |
| 1 | 1 | 1 | 1 |
Combining logic gates creates complex Boolean expressions, e.g., Q = (A AND B) OR (NOT C).
非门仅将输入取反：NOT 0 = 1, NOT 1 = 0。组合逻辑门可以创建复杂的布尔表达式，例如 Q = (A AND B) OR (NOT C)。
4. Networking Fundamentals | 网络基础
A Local Area Network (LAN) connects computers in a small area, e.g., a school or home, while a Wide Area Network (WAN) connects LANs over large distances, such as the Internet. Network topology defines how devices are connected. Star topology uses a central switch, providing better reliability; bus topology uses a single backbone cable, which is simpler but less fault-tolerant.
局域网 (LAN) 连接小范围内的计算机，例如学校或家庭；广域网 (WAN) 连接长距离的局域网，例如互联网。网络拓扑定义了设备的连接方式。星形拓扑使用中央交换机，可靠性更高；总线拓扑使用单一主干电缆，更简单但容错性较差。
Key protocols include TCP/IP (Transmission Control Protocol/Internet Protocol) that manage data transmission. Each device has a unique MAC (Media Access Control) address and an IP address (e.g., 192.168.1.10) for identification. Common application-layer protocols: HTTP for web, FTP for file transfer, SMTP for email.
关键协议包括管理数据传输的 TCP/IP（传输控制协议/互联网协议）。每个设备都有一个唯一的 MAC（媒体访问控制）地址和一个 IP 地址（如 192.168.1.10）用于识别。常见的应用层协议：HTTP 用于网页，FTP 用于文件传输，SMTP 用于电子邮件。
5. Cybersecurity Threats and Prevention | 网络安全威胁与防护
Malware is malicious software including viruses, worms and trojans. Phishing emails trick users into revealing personal data. A brute-force attack tries all possible passwords. Denial of Service (DoS) floods a server with traffic to make it unavailable.
恶意软件包括病毒、蠕虫和木马。网络钓鱼邮件诱骗用户泄露个人信息。暴力攻击尝试所有可能的密码。拒绝服务攻击 (DoS) 用流量淹没服务器使其不可用。
Protection methods include firewalls (filter incoming/outgoing traffic), encryption (scrambling data so only authorised parties can read it), strong passwords and regular software updates. Ethical hacking helps identify weaknesses before they are exploited.
防护方法包括防火墙（过滤进出流量）、加密（把数据加密，只有授权方可以读取）、强密码和定期软件更新。道德黑客在漏洞被利用前帮助发现弱点。
6. Algorithms and Flowcharts | 算法与流程图
An algorithm is a step-by-step procedure to solve a problem. It can be expressed using flowcharts, pseudocode or structured English. Sequence, selection (if-else) and iteration (loops) are the three control structures.
算法是解决问题的分步过程。它可以用流程图、伪代码或结构化英语表示。顺序、选择（if-else）和迭代（循环）是三种控制结构。
Flowchart symbols include ovals for start/end, rectangles for processes, diamonds for decisions and parallelograms for input/output. Consider an algorithm to output the larger of two numbers:
流程图符号包括开始/结束的椭圆、处理过程的矩形、判断的菱形和输入输出的平行四边形。考虑输出两个数中较大值的算法：
- Start → Read num1, num2
- If num1 > num2 then output num1 else output num2
- End
开始 → 读取 num1, num2。如果 num1 > num2，则输出 num1，否则输出 num2。结束。
7. Programming Concepts | 编程概念
umbers), char (single character), string (text), Boolean (true/false). Assignment uses the '=' operator, e.g., score = 0.
变量存储程序执行期间可以改变的数据。常见数据类型：整型（整数）、实型/浮点型（小数）、字符型（单个字符）、字符串（文本）、布尔型（真/假）。赋值使用 "=" 运算符，例如 score = 0。
Programs use arithmetic (+, -, *, /) and comparison operators (==, ! else and loops (while, for) enable control flow. For example, a simple loop in pseudocode:
程序使用算术运算符（+, -, *, /）和比较运算符（==, !=, >, <）。选择语句 if-else 和循环（while, for）实现控制流。例如，简单的伪代码循环：
FOR i ← 1 TO 5 -> OUTPUT i -> NEXT i
首先 i 从 1 到 5 循环，输出 i 的值。
8. Searching and Sorting Algorithms | 搜索与排序算法
Linear search checks each element sequentially until the target is found or the list ends. Its worst-case time complexity is O(n). Binary search requires a sorted list and repeatedly divides the search interval in half, giving O(log n).
线性搜索按顺序检查每个元素，直到找到目标或列表结束。其最坏情况时间复杂度为 O(n)。二分搜索要求列表已排序，并重复将搜索区间减半，时间复杂度为 O(log n)。
Bubble sort repeatedly compares adjacent items and swaps them if they are in the wrong order. It is simple but inefficient, O(n²). Insertion sort builds a sorted portion one item at a time, also O(n²) but generally faster than bubble sort for small datasets.
冒泡排序反复比较相邻项，如果顺序错误则交换它们。它简单但效率低，为 O(n²)。插入排序每次将一个项插入到已排序的部分中，也是 O(n²)，但对于小数据集通常比冒泡排序快。
| Algorithm | Best Case | Worst Case | Requires Sorted Data? |
|---|---|---|---|
| Linear Search | O(1) | O(n) | No |
| Binary Search | O(1) | O(log n) | Yes |
| Bubble Sort | O(n) | O(n²) | N/A |
9. Ethical, Legal and Environmental Issues | 伦理、法律与环境问题
The Data Protection Act governs how personal data may be collected, processed and stored; it requires that data be used fairly, kept secure and not held longer than necessary. The Computer Misuse Act makes unauthorised access to computer material illegal.
数据保护法规定了个人数据的收集、处理和存储方式；它要求数据被公平使用、安全保存且保存时间不超过必要。计算机滥用法将未经授权访问计算机材料定为非法。
Intellectual property rights protect creative works; using software without a licence is piracy. Open source software encourages sharing but still carries licence rules. E-waste from discarded devices harms the environment; recycling and responsible disposal are vital.
知识产权保护创造性作品；无许可证使用软件是盗版行为。开源软件鼓励共享，但仍须遵守许可规则。废弃设备产生的电子垃圾危害环境；回收和负责任的处理至关重要。
10. Computational Thinking | 计算思维
Computational thinking involves decomposition (breaking a problem into smaller parts), pattern recognition (identifying similarities), abstraction (focusing on important details and ignoring irrelevant ones) and algorithm design (creating a step-by-step solution).
计算思维包括分解（将问题分解为更小的部分）、模式识别（找出相似之处）、抽象（专注于重要细节而忽略无关细节）和算法设计（创建分步解决方案）。
For example, when designing a software to manage a library, you would decompose it into book cataloguing, user accounts and borrowing modules; abstract away the database technology; and then design algorithms for searching and reserving books. This approach is fundamental to programming and problem-solving.
例如，设计一个图书馆管理软件时，可以将其分解为图书编目、用户账户和借阅模块；抽象掉数据库技术；然后设计搜索和预订图书的算法。这种方法对于编程和问题解决至关重要。
Published by TutorHao | Computer Science Revision Series | aleveler.com
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